Heretofore, in the ink-jet printer device, ink is jetted from a nozzle corresponding to a recording signal and characters and graphics based on said recording signal can be recorded on the recording medium such as paper and film.
FIG. 11 shows an example of the construction of a conventional ink-jet printhead 1 that has been used in the ink-jet printhead device. This ink-jet printhead comprises a passage plate 2 of which one surface 2A is affixed to a nozzle plate 3 and the other surface 2B is affixed to a piezoelectric actuator 4.
In this case, pressure chambers 2C comprised of multiple concave parts are arranged on one surface side 2A of the passage plate 2 along the direction shown an arrow x1 at established intervals. And ink can be continuously supplied from the ink cartridge (not shown in FIG.) into these pressure chambers 2C through a common passage 2D respectively.
Moreover, at the edge of each pressure chamber 2C, a through path 2E is formed cutting through the passage plate 2 in the direction of its thickness (in the direction of an arrow z1), and nozzles 3A formed of multiple through holes are formed cutting through the nozzle plate 3 corresponding respectively to each through path 2E along the direction of an arrow x1 at established intervals.
On the other hand, as shown in FIGS. 11 and 12, a piezoelectric actuator 4 is comprised of multiple piezoelectric elements 6 arranged on one surface of the vibration plate 5 formed of flexible materials along the direction of an arrow x1 facing respectively to pressure chamber 2C of the passage plate 2 via said vibration plate 5, and it is fixed to said passage plate 2 affixing the other surface of the vibration plate 5 onto the other surface 2B of the passage plate 2.
At this point, each piezoelectric element 6 is polarized in the direction of its thickness (in the direction of an arrow z1). And as shown in FIG. 9, upper electrode 7A and lower electrode 7B are formed on one surface and the other surface of the piezoelectric element 6 respectively. And thus, by causing voltage difference between the upper electrode 7A and the lower electrode 7B, the piezoelectric element 6 can be deflected in the direction to displace the vibration plate 5 toward inside of the corresponding pressure chamber 2C according to the piezoelectric effects (the direction opposite to the arrow z1).
Thus, in this type of ink-jet printhead 1, by generating the voltage difference between the upper electrode 7A and the lower electrode 7B of the piezoelectric element 6 and displacing the vibration plate 5 toward inside of the corresponding pressure chamber 2C, the pressure corresponding to that deviation can be generated in the pressure chamber 2C and ink in said pressure chamber 2C can be jetted outside from the nozzle 3A under this pressure via the through path 2E.
In the ink-jet printhead 1, as disclosed in Japan Patent Laid-open No. H6-320739 bulletin, for example, the piezoelectric actuator 4 was manufactured by bonding each piezoelectric element 6 onto the vibration plate 5 using adhesives after the vibration plate 5 and piezoelectric element 6 were formed independently.
However, according to the conventional manufacturing method, it was difficult to paste multiple fine piezoelectric elements 6 precisely onto the fixed positions of the vibration plate 5. In this connection, if the position on which the piezoelectric element 6 is to be pasted is displaced from the fixed position, the pressure based on deflection of piezoelectric element 6 cannot be generated in the corresponding pressure chamber 2C and accordingly the printing becomes unstable.
Furthermore, generally the larger the size of electric field to be printed becomes, the more the piezoelectric element warps. Therefore, in order that the conventional ink-jet printhead 1 can be driven with low voltage, each piezoelectric element 6 should be formed as thin as possible making the distance between upper electrode 7A and the lower electrode 7B short and at the same time, the vibration plate 5 is formed as thin as possible and in practice, the conventional vibration plate 5 and each piezoelectric element 6 have the thickness of less than 30 (μm) respectively.
However, in order to shorten the natural vibration cycle and increase the corresponding speed, the vibration plate 5 is made up of such as glass and ceramic materials having high Young's modulus as its material. But it is difficult to make a thin sheet having less than 30 (μm) using glass or ceramic materials. And heretofore, the vibration plate 5 has been made by grinding the glass plate or ceramic plate having the thickness of several hundreds (μm) till it becomes thinner than 30 (μm).
Accordingly, in the conventional ink-jet printhead 1, it caused problems due to the costly and time consuming manufacturing process of the vibration plate S and poor productivity. Moreover, the piezoelectric element 6 having thinner than 30 (μm) was obtained by grinding it in the same manner as the vibration plate 5 and the realization of a piezoelectric actuator 4 having higher productivity has been desired.
Moreover, in the conventional ink-jet printhead 1, since the vibration plate S and each piezoelectric element 6 are formed extremely thin, these vibration plate 5 and piezoelectric element 6 are easily damaged. And in addition to the poor productivity as described above, it has caused the problem in handling at the time when manufacturing the vibration plate 5 and each piezoelectric element 6.